Subject: [nwcrg] About the concept of "symbol"

From: Vincent Roca <[email-masked]>
Date: Mon, 23 Jun 2014 11:21:40 +0200

Hello Marie-José,

NB: I've created a new thread for this topic...

The important aspect (with clear architectural implications) is:

	What are the boundaries of the "coding component" concept in the NWC approach?

From my point of view, it's similar to the FEC building block in the RMT/FECFRAME terminology. It's just the
mathematical transform that generates output symbols given input symbols. By "just" I mean the Finite Field
operations plus some signaling. All the mathematical details are hidden inside this "coding component".
All the rest, all the intelligence, is a protocol  mechanism that relies on this low level "coding component".

This is what I presented at London:
	http://www.ietf.org/proceedings/89/slides/slides-89-nwcrg-7.pdf

If the "symbol" is the unit of data that is fed as an input to the "coding component" and the unit of data that is output
by the "coding" component, you can probably keep this "symbol" term. The key question is: "how to create the
symbol set at an intermediate re-encoding node given a set of incoming packets"?

We had similar discussions within the FECFRAME WG. In that context, the units of data provided by the sending
application need to be grouped into source blocks, arranged inside tables, padded, sometimes partitioned, and
prepended with additional pieces of information (namely a flow ID and a length field). Only then one can derive the
"symbols" that are given to the FEC component. The problem is different at RMT but we end up with symbols given
an input object.

So "in-network re-encoding" affects essentially the intelligent part (i.e. protocol) we build on top of the "coding
component" and the selection of the appropriate "coding component" inside this protocol.

Does it make sense?
Cheers,

   Vincent

Le 23 juin 2014 à 09:36, Marie-Jose Montpetit a écrit :

> Actually in order to make some progress on the taxonomy I propose to enhance the FECFRAME taxonomy with an input on the significance of the in-network re-encoding which modifies the concept of "symbol".
> 
> Any comment?
> 
> /mjm
>